My understanding is that Saylor is actually just stating upfront the thing that will happen repeatedly every year in the future.

There's nothing wrong with that.
The key to the MSTR game has never been "never sell," but rather that each year net buy > net sell.
As long as this direction remains unchanged, it is still that BTC absorption machine.
The only issue is: the first time selling, the market isn't used to it, and emotions will spike, faith will be tested.
But many things are like this; the first time hurts the most.
After surviving this round of stress testing, the market will digest this mechanism, and later on, it will gradually get used to it.
Saylor's real proof isn't "not selling," but rather "selling a little doesn't affect continuing to buy more."